Recuperator



March 18, 1930. G. D. MANTLE ET AL 1,750,850

RECUPERATOR I Filed May 25, 1927 3 Sheets-Sheet l March 18, 1930. e. D. MANTLEREIT AL 1,750,850

RECUPERATOR Filed May 23, 1927 3 Sheets-Sheet 2 I I 2 I I I o oloi o I I I I W1 b I \J.\ h o QIOI O n I n n h I F March 18, 1930. s. D. MANTLE ET AL RECUPERA'I'OR.

Filed May 23 1927 5 Sheets-Shee t 3 Patented Mar. 18, 1930 UNITED STATES P TENT OFFICE ASSIGNORS, BY MESNE ASSIGNMENTS,

TO SURFACE COMBUSTION COMPANY OF TOLEDO, OHIO, A CORPORATION OF NEW YORK RECUPERATOR Application filed May 23,

' This invention relates to recuperators and I more particularly to a recuperator comprlsing a unit adapted to be united with other units to form a heat exchanger of any de- 6 sired capacity. I

4 Heretofore diin'culty has been experienced in recuperators operating to transfer heat from one gas to another in that corrosion has occurred at the joints of the recuperator. We provide an improved recuperator wherein all of the joints are disposed within the ducts adapted to convey one of the gases, either the heating gas or the heated gas. The present invention will be described particularly with respect to a recuperator adapted to transfer heat from a heating gas to a r, in which case all of the joints w1ll be disposed within the air passages.

In the accompanymg drawings illustrating the present preferred embodiment of our invention:

Figure 1 is a sectional elevatlon of a recuperator embodying our lnvention;

Figure 2 is a sectional view on the lm 2 II-II of Figure 1;

Figure 3 illustrates two sections of our recuperator joined together to form a slngle heat exchanger; I

' Figure 4 is a cross-sectlonal view on the so line IV-IV of Figure 1;

Figure 5 is across sectlonal new on the line V-V of Figure 1; 4

Fi ure 6 is an enlarged detail view on the line %I-VI of Fig. 1 of the joint employed as between the passages; and

Figure 7 is an enlar ed cross-sectional View on the'line VIIVI of Figure 3,

' Referring to the illustrated embodiment, there is shown in Figure 1 a recuperator having air inlet passages 2 and 3 and an outlet 4. The inlet 2 communicates with a tortuous passage 5 formed between side plates 6 I (Figure 4) and bafiles 7 extendlng between the side plates. The passage 5 communicates with an outlet duct 8 which terminates in the outlet 4. The inlet 3 communicates with the passage 9 leading to the opposite end of the recuperator. A cross-passage 1O conducts the I air transversely across the recuperator from 60 the passage 9, the passage 10 being connected short duct 14 lying with 1927. Serial no. 193,446.

to a similar assage 11 by a duct 12 located at the end 0 the passages 10 and 11, and lying within the outlet duct 8. The passage 11 communicates with a cross-passage 13 extending parallel thereto, connection between the passages 11 and 13 l :ing effected by a in he inlet passage 9. The end of the passage 13, opposite the duct 14, communicates with the outlet duct 8. The passages 10, 11 and 13 are preferably formed as hereinafter described.

The heating gas enters the recuperator from the right, as viewed in Figure 1, and flows longitudinally through a straight unobstructed passage 15 to the opposite end thereof (Figure 4). The recuperatoris provided with a number of similar. passages to those described. The. recuperator being formed of a number of similar passages, may be readily built up to form a convenient unit, such as shown in Figures 4 and 5. These units may be joined together to build up a heat exchanger of any desired size, as shown in Figure 3.

The air entering the recuperator through 'the inlets 2 and 3 is divided into two streams,

one of which flows in a tortuous path counter current to the heating gas, flowing substantially to the end of the recuperator at which the heating gas enters, but for convenience being conducted back to the end of the recuperator at which the air enters, before being discharged; The other air'streamis conducted directly to the end of the recuperator at which the heating gas enters, and is passed back and forth across the end of the recuperator several times to effect cooling of the incoming heating gases to avoid burning out the recuperator if the incoming heating gases be initially too hot. The two streams of heated air are eventually united. The relative quantities of air in the two stream may be proportioned as desired.

The heat transferred to the heated air is conserved by insulation 16 and 17 lying along the exterior walls-of the inlet andoutlet pas-- sages 8 and 9. It will be evident from Fig vures 4 and 5 that when two sections of recuperator are joined to formj'a large heat exchanger, the insulating portions will lie'adjacent one another (Figure 7). r The plates forming the walls of the passages within the recuperator are spaced apart by the baflles 7 which are preferably channel shaped to serve to stiffen the stru ture. The passage wall plates are connected to the walls of the ducts 8 and 9, extending into the interiorv of the ducts where they are fastened to flanged portions of the wall of the ducts. The joint is preferably riveted as well as being welded to give maximum mechanical strength and insure that there be no gas leakage. The joints being gas-tight obviate seepage of the heating gas between the joined 'portions so that the passages conducting the heating gas are gas-tight and free from projecting portions or joints which are subject to corrosion. The joints which are necessarily formed in the cgnstruction of the recuperator are all disposed within the air passages, and the heating gases cannot wash the joints. The plates forming the recuperator are preferably made of an alloy or of other material which is heat resistant and corrosion resistant. By our improved construction em bodying an advantageous disposition of the joints, the alloy or treated plates present only corrosion resistant surfaces to the heating gases. Y v k As shown in Figure 5, the short connecting ducts 12 and 14 which extend into the passages 8 and 9 are connected to the flanged members which engage the passage wall plates. The joints in these ducts are also protected from contact with the heating gases for the reason that the ducts are disposed wholly within air passages.

The transverse passages 10, 11 and 13, which serve to convey the coolest air across the hottest portion of the recu erator are preferably formed, as shown in Figures 2 and l 6, so that the joints lie within an air passage and are protected from the corrosive action of the heating gases. As shown in Figure 6, the passage walls 13 of the'passage 13 are bent together to form a closed joint having projecting flanges 13 lyin adjacent one another. Thewalls 6 which oin the projecting flange portions 13 are folded so that the flange contacting portions are disposed within the walls 6, placing the entire joint inside of the air passage 5, away from the heating gases. The joint is preferably riveted and welded to insure mechanical strength and gastight construction.

' Figures 4 and '5 illustrate the construction of the ducts 8 and 9. The recuperator is pref-"changer.

erably formed-by joining the plates forming the gas passages together with channel shaped portions 18 and 19. .The side walls of the ducts 8 and 9 are formed by'flanged plates 20 which are riveted to the plates 6 and 6' forming the sides of the passage walls. These plates 20 extend longitudina y of the recu- .form walls of the ducts 8 and 9. The insulation 16 and 17 lies withinthe channel bars 21 and is retained there by flanged plates 22 which form the outer wall of the recuperator. The flanged plates 22' have outwardly extending flanges 22* adapted to overlie the flanges 21 of the channel bars 21 so that the plates 20, channels 21 and plates 22 may all be connected together by rivets through the flanged portions 22, 21 and the plates 20. Thus a single row of rivets along each side serves to maintain the insulation in place, retaining the end wall of the recuperator, and forming the gas-tight joint between the walls of the ducts 8 and 9. This construction "greatly simplifies assembly operations and forms an eflicient. closure from a mechanical standpoint, both with regard to strength and prevention of gas leakage. I v

The end plates 22 are provided with inturned flanges 22 which serve as connecting portions when several recuperator unitsare joined to form a single large heat exchanger, as shown in Figure 7 Connection between the flanges 22 is effected by means of a plate 23 which is bolted to Figure 3.

It will thus be seen that our recuperator may be constructed in convenient units which may be assembled together to form heat exchangers of any desired capacity.- We further provide an improved recuperator wherein the joints are all disposed within passages subjected to but one of the operating gases The recuperator shown in Figure 1 is illustrated ina horizontal position, but it will be understood that the recuperator may be "operated in a vertical position in which case the flanges, as shown in' units are assembled to .form a large heat ex- Insulating rmaterial may. then be applied to the side portions, as desired.

It will be understood that the term' recuperator. is used herein as a word of general definition and not of limitation, and that the term is meant to include air heaters and similar structures, as well'as heat exchangers. While we have illustrated and'described the present preferred embodiment of our invention, it will be understood that the invention is not limited thereto, but may be otherwise embodie'd within the scope of the following claims.

We claim:

1. A recuperator having passages adapted to conduct air and having spaces through which hot gases are circulated, said recuperator comprising plates joined together, said joints being all disposed within the air passages out of contact with the hot gases.

2. A recuperator comprising a plurality of joined members forming passages for heating and heated gases, all of the joints being disposed within the passages for the heated gases.

3. A recuperator having a gas passage and an insulating medium ad acent said passage, at least two of the walls of said passage comprising substantially arallel plates, a channel bar intermediate t e plates and .forming a third wall of'the passage, insulating material adjacent the channel bar, and a flanged. plate intermediate the flanges of the channel bar and adapted to retain the insulating medium within the channel bar.

4. In a recuperator, a pair of adjacent passages, the walls of one of said passages being inwardly bent and outwardly flanged to form a closure, the flangeslying in contact with one another, the walls of the adjacent passage being folded inwardly, the inner ends of said folds lying in contact with the flanged portions of the adjacent passage walls, and means securing the .folds and flanges toge'ther'to form a gas-tight joint.

5. A heat exchanger comprising a plurality of recuperating units joined together,

said recuperator units comprising a plurality of plates joined together to iormgas passages and insulating portions lying outside of the gas passages, said insulating portions being adapted to lie adjacent one another when the units are joined together to form a substantially continuous insulating covering on the outside of the heat exchanger.

'6. In a recuperator, a pair of plates forming the sidewalls of a duct, a channel bar interposed between the plates and forming a third wall of the duct, insulating material lying within the channel bar, a flanged plate disposed outside the insulatmg material and adapted to hold the same withinthe channel bar and means connecting the first mentioned plates, the channel bar and the flanged plate,

whereby the insulating material is retained in place and a gas-tight joint is formed between the channel bar and the plates formin the walls of the duct.

In a recuperator, a plurality of substantiall parallel plates forming passages for I heating and heated gases, a plurality of baflie members disposed transversely of the longitudinal axis of the plates forming passages transversely of said axis, and ducts connecting adjacent transverse passages, said ducts lying at the edges of said plates whereby the transverse passages are longer than the width of the plates.

tially parallel plates forming gas passages, a conduit disposed atthe edge of said plates, a wall of said conduit comprising'a plurality of channel shaped members connecting said plates, the joints between the plates and channel members extending into the conduit.

9. A recuperator having hotigas' circulating passages and air heating passages, and constructed of alternated longitudinally extending channel bar members and plate members lying in planes at right angles to each other, the joints between the channel bar members and the plate members being welded and being turned outwardly so that they are outside the hot gas passages. I

10. A recuperator unit having hot gas circulating passages and air heating passages, said recuperator being constructed of longitudinally extendingplates, channel bars between adjacent plates holding them in spaced flanges turned outwardly, the joints ween the channel bars and the plates being gastight, longitudinally extending flanged side relation,"' the channel bars havinge their a v ing conduits at each side of the unit, heat insulating material in said last mentioned channel bars, and a flanged member set in the last named channel bars to retain the heat insulating material in place.

11. A recuperator unit having hot gas circulating passages and air heating. passages, said recuperator being" constructed of longitudinally extending plates, channel bars betwen adj acent plates holding them in spaced relation, the channel I bars having their flanges turned outwardl the joints between the channel bars and t e plates being gastight, the spaces between-alternate pairs of plates being air passages, the plates at one I end being turned inwardly into the air circulating passages, other pairs of spaced. apart plates having their edges extending between the inwardlyturned ends of the air passages and .forming a gas tight joint therewith, thesaid joint ly ng entirely in the air passage and being protected fromcontact with the gases in the hot gas passages.

12. A recuperator comprising a plurality of jointed .members forming passages 'for heating and heatedgases, all of the joints longitudinally and transversely of the structure bein disposed .within the passages for: the heate gases.

8. In a recuperator, a plurality of substan- ('70 13. .recuperator' comprising a plurality of jointed metal' members forming passages for heating and heated gases, all of the meeting edges of the metal members projecting into passages for the heated gases and being Welded within said passages.

14. In ametal recuperator structure, a plurality 'of metal members joined together to provide hot gas and air circulating passages,

all meeting edges between the metal members both longitudinally and transversely of the structure projecting into the air passages and providing heat dissipating fins or projections within said air passages.

15. In a metal recu erator structure, a plurality of metal mem ers joined together to provide hot gas and air circulating passages,

all meeting edges between the metal members both longitudinally and transversely of the structure projecting into the air passages and providing heat dissipating fins or projections withinsaid air passages, said meeting edges being welded together with the welds in the air circulating passages.

16. In a metal recuperator structure, a series of spaced metal plates arranged in pairs and providing alternate air and gas circulating passages, the plates of a pair having some of the edges turned inwardly and jointed within the air passage formed between them whereby the joint is protectedv from contact with the gases in the gas cir-' .culating passages. -In testimonywhereof we have hereunto set our hands.

GREGORY D. MANTLE. THEODORE W. MUNFORD. 

